A generator housing (1) of an engine generator is connected to a gearbox casing (17) via a cover plate (23) that bears the rotor shaft (5). The cover plate has a two-piece design and includes a bearing retainer ring (13) for a rotor shaft bearing (11) made of a rigid material and fastened only to the gearbox casing, and a heat-conducting ring (21) connected with both the gearbox casing and the generator housing. A centering cylinder (18) molded to the bearing retainer ring centers the generator housing and thus the stator (3) and rotor (4) while a spacer ring (20) and/or an adjustable spacer ring (10) ensure the exact axial positioning of the rotor or bearing retainer ring. The generator of this design is safe to operate and has a long service life.
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1. A generator for an engine comprising:
a generator housing;
a stator;
a rotor, the stator and rotor housed in the generator housing;
a rotor shaft for supporting the rotor;
a cover plate that is flanged for fitting to a gearbox casing and which includes an integrated bearing for the rotor shaft; the cover plate including:
a bearing retainer ring detachably connectable to the gearbox casing and made of a rigid high-strength material for receiving the bearing; and
a separate heat-conducting ring connectable to the gearbox casing and the generator housing and made of a highly heat-conducting material.
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20. The generator according to
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This application claims priority to German Patent Application DE 10 2005 049 879.5 filed Oct. 17, 2005, the entirety of which is incorporated by reference herein.
The invention relates to a generator for an engine having a generator housing that houses a stator and rotor, and a cover plate that includes a bearing for the rotor shaft and is flanged to a gearbox casing.
Generators flanged to the gearbox casing via a cover plate have been known for a long time but they cause problems because the functioning of the generator is adversely affected and its service life significantly reduced by the considerable quantity of heat produced by its rotor and stator. Engineers have tried to solve this problem by improving heat dissipation from the generator housing via its cover plate to the gearbox casing, in that the cover plate was made of a material with high thermal conductivity, like the aluminum alloy used here, so that the heat can be dissipated from the generator housing (that is also made of an aluminum alloy) via the cover plate into the gearbox casing.
The rotor shaft is typically supported by a steel ball bearing that is integrated into the cover plate. If the cover plate involves two materials with different heat conductivities, there is the disadvantage that the steel bearing of the rotor shaft cannot be incorporated firmly enough into the aluminum cover plate, since the two materials differ in thermal expansion. As the aluminum cover plate shows comparatively little stiffness and does not meet the dynamic requirements of high rotor speeds and a durably stable seat of the bearing in the cover plate, the bearing of the rotor shaft does not have a long service life. An insert made of a high-strength and rigid material such as a titanium alloy must be used in the cover plate. An increased clearance can result between the shell of the bearing and the casing results in jams and vibrations, which eventually damages the bearing, the stator and the rotor.
The proposal to make the entire cover plate of a high-strength material such as steel or titanium has solved the problem described above and represents today's state of the art. However, this results in comparatively poor heat conductivity and excessive operating temperatures of the generator stator, leading to increased failure rates of these generators. The proposal to create as large a heat transfer surface as possible by making the cover plate large-volume is doomed to failure as this increases the volume and weight of the cover plate, the latter effect being particularly undesirable in aircraft engines. Cooling fins on the generator housing would be an excellent alternative solution for heat dissipation in normal operating conditions but fail here because in the event of a fire a greater heat input with unchanged poor thermal conductivity towards the gearbox will result in early generator failure, which prevents it from meeting the five-minute minimum functionality requirement in the event of a fire to supply power to the electronic control module and overspeed protection unit for safe engine shutdown.
It is an object of this invention to design a generator flanged to the gearbox casing of an engine in such a way that it ensures an exactly centered bearing of the rotor shaft and exact alignment of the rotor with the stator while as great a heat quantity as possible is dissipated from the stator housing for a long service life of the generator.
This object is achieved according to the invention by a generator designed according to the characteristics described herein and its coupling to the gearbox casing. Advantageous improvements and useful aspects of the invention are described below.
The major characteristic of the invention is a two-piece design of the cover plate that encloses the generator and is flanged to the gearbox casing, said cover plate having a bearing retainer ring that is only screwed to the rotor shaft and the gearbox casing and made of a high-strength rigid material, and a separate heat-conducting ring connected both to the gearbox casing and to the generator housing made of a highly heat-conductive material. As the heat is separately conducted directly to the gearbox casing and the rotor shaft is supported separately in a bearing retainer ring only connected to the gearbox casing and made of a poorly heat-conductive, stiff material, operationally safe centered bearing of the rotor shaft and the rotor in the stator is ensured regardless of any movements caused by heat, and the generator can be operated without stator overheating so that a long service life can be achieved.
This provides an opportunity to rework existing components such as the bearing retainer ring or to continue to use the existing stator, thereby reducing the expenses of optimizing the connection of the generator to the gearbox casing.
In another embodiment of the invention, a centering cylinder pointing towards the generator is molded to the bearing retainer ring. This cylinder tightly surrounds the peripheral surface of the generator housing and causes exact centering of the rotor in the stator. The purely radial sealing is less sensitive to varying component heights of the bearing retainer ring and the heat-conducting ring and allows greater manufacturing tolerances with regard to the heights of the heat-conducting ring and the bearing retainer ring.
The bearing retainer ring can be connected to the gearbox casing via a spacer ring to ensure tightness and correct axial arrangement of the centering cylinder to the generator housing or of the rotor to the stator. Spacer rings of various thicknesses are provided that guarantee the proper setting accuracy.
The bearing retainer ring is screwed to the gearbox casing using fastening eyes. As the heat-conducting ring encompasses the bearing retainer ring at a relatively narrow spacing and is in contact with the gearbox casing, two recesses are molded into the edge of the heat-conducting ring that points towards the gearbox casing, and the fastening eyes engage in these recesses.
According to yet another characteristic of the invention, the rotor is supported at its front end by a jacket that encompasses the rotor shaft, preferably via an adjustable spacer ring that is available in various thicknesses to ensure exact axial alignment of the rotor with the stator.
In yet another embodiment of the invention, the heat-conducting ring can be connected to the bearing retainer ring by some type of fit.
Finally the heat-conducting ring can also be directly molded to the generator housing, and in this case the centering ring of the bearing retainer ring with its circumferential groove and inserted O-ring acts against the inner surface of the generator housing extended by the heat-conducting ring. In this application, the generator housing has a direct thermal connection with the gearbox while at the same time the more rigid material required for optimum support is utilized. This makes it possible to keep the number of components low for any new design, to apply greater dimensional tolerances to the manufacturing of the centering cylinder of the bearing retainer ring, and to limit axial rotor orientation towards the stator to the selection of an adjustable spacer ring that is available in various thicknesses and placed between the rotor front end and the collar that encompasses the rotor shaft.
Embodiments of the invention are explained in greater detail with reference to the figures, wherein:
As shown in the Figures, the magneto-electric generator includes a generator housing 1, a stator 3 mounted to its inner wall and comprising induction coils 2, and a rotor 4 equipped with permanent magnets 7 that is held on a rotor shaft 5 using a fastening nut 6. An oil splasher disk 9 is attached to the rotor shaft 5 using a jacket 8 connected to it. The rotor 4 is supported axially at the front end of the jacket 8 that points towards the generator housing 1. The front end of the rotor is supported by the jacket 8 using a first adjustable spacer ring 10 that is set to a specific thickness. Adjustable spacer rings 10 are available at various thicknesses for exact axial alignment of the rotor 4 with the stator 3.
An antifriction bearing 11 whose outer bearing shell 12 is attached to a bearing retainer ring 13 made of a titanium alloy, a rigid but poorly heat-conductive material, is provided for supporting the rotor shaft 5. As can be seen in
A centering cylinder 18 that stretches in axial direction towards the stator is molded onto the bearing retainer ring 13, and an O-ring 19 on its inner surface holds a peripheral surface of the cylindrical generator housing 1 (
The outer surface of the centering cylinder 18 of the bearing retainer ring 13 is encompassed by a heat-conducting ring 21 made of a highly heat-conductive material, in one embodiment, an aluminum alloy. The heat-conducting ring 21 is in contact with both the generator housing 1 and the gearbox casing flange 16 of the gearbox casing 17 so that the heat of the generator housing 1 is dissipated towards the gearbox casing 17, thereby ensuring trouble-free operation and a long service life of the magneto-electric generator. The heat-conducting ring 21 is fastened between generator housing 1 and gearbox casing 17 using mounting links 24 molded to the heat-conducting ring 21 and associated first mounting holes 25 (
As
In this way, the bearing retainer ring 13 with centering cylinder 18 and heat-conductive ring 21 form a joint two-piece cover plate 23 that is mounted between the generator housing 1 and gearbox casing 17 and that ensures good heat dissipation from the generator housing 1 to the gearbox casing 17 and dynamically stable support in the bearing retainer ring 13 made of a stiffer material, as well as centered and axially exact alignment of the rotor 4 with the stator 3.
The heat-conducting ring 21 and the bearing retainer ring 13 with centering cylinder 18 are independently connected to the gearbox casing 17. Positioning and alignment of the bearing retainer ring 13 and the rotor 4 with the stator 3 are not influenced by the different expansion behavior of heat-conducting ring 21 and bearing retainer ring 13 as the rotor shaft 5 that is radially supported on both sides is axially guided by the interaction of rotor 4 and stator 3 as produced by a magnetic field and can compensate small relative movements of the two components in axial direction.
According to
The spacer ring 20 is also dispensable if the O-ring 19—unlike in FIGS. 1 and 5—is arranged in such a way that it forms a radial seal between the centering cylinder 18 and an inner peripheral surface of the generator housing 1 as shown in
Another embodiment of the cover plate 23 according to the invention is shown in
Patent | Priority | Assignee | Title |
10014758, | Jul 06 2012 | Hamilton Sundstrand Corporation | Method of assembling integrated drive generator housing and bearing |
10205365, | Mar 30 2016 | Milwaukee Electric Tool Corporation | Brushless motor for a power tool |
10432065, | Mar 30 2016 | Milwaukee Electric Tool Corporation | Brushless motor for a power tool |
10519809, | Oct 21 2016 | Pratt & Whitney Canada Corp | Liner for mounting socket of magnesium housing of aircraft engine |
10673305, | Mar 30 2016 | Milwaukee Electric Tool Corporation | Brushless motor for a power tool |
10804778, | Jul 06 2012 | Hamilton Sundstrand Corporation | Integrated drive generator housing |
10931167, | Mar 30 2016 | Milwaukee Electric Tool Corporation | Brushless motor for a power tool |
11118705, | Aug 07 2018 | General Electric Company | Quick connect firewall seal for firewall |
11496022, | Mar 30 2016 | Milwaukee Electric Tool Corporation | Brushless motor for a power tool |
11522415, | Mar 31 2020 | NIDEC CORPORATION | Motor |
11635053, | Nov 19 2020 | Schaeffler Technologies AG & Co. KG | Starter-generator with power electronic unit |
11735963, | Dec 26 2019 | Sanyo Denki Co., Ltd. | Polygonal frame structure with armature core with connected and open core sheets inside the frame |
11831201, | Sep 23 2020 | Hyundai Mobis Co., Ltd. | Motor with split core stator with two support rings |
8227931, | Jun 06 2007 | STEYR MOTORS BETRIEBS GMBH | Generating unit comprising a combustion engine and a generator |
9154011, | Jul 06 2012 | Hamilton Sundstrand Corporation | Integrated drive generator housing |
Patent | Priority | Assignee | Title |
2794930, | |||
3742264, | |||
4286187, | Apr 14 1978 | Robert Bosch GmbH | Bearingless generator and rotary machine combination |
5796190, | May 29 1995 | Denyo Kabushiki Kaisha | Engine-driven permanent magnetic type welding generator |
6114784, | Jun 22 1998 | Nissan Motor Co., Ltd. | Motor with cooling structure |
6710482, | Aug 25 2001 | SAFRAN POWER UK LTD | Generator |
7042121, | Jul 30 2004 | BROSE FAHRZEUGTEILE GMBH & CO KOMMANDITGESELLSCHAFT, WURZBURG | Cooling fan with electric motor |
AT151891, | |||
DE20111265, | |||
DE2333385, | |||
DE2816180, | |||
EP1289099, | |||
JP8019215, | |||
WO8806371, |
Executed on | Assignor | Assignee | Conveyance | Frame | Reel | Doc |
Sep 28 2006 | Rolls-Royce Deutschland Ltd & Co KG | (assignment on the face of the patent) | / | |||
Sep 28 2006 | VAN DER WOUDE, MATTHIJS | Rolls-Royce Deutschland Ltd & Co KG | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 018359 | /0101 |
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